English

On Berge-Ramsey problems

Combinatorics 2019-06-07 v1

Abstract

Given a graph GG, a hypergraph H\mathcal{H} is a Berge copy of FF if V(G)V(H)V(G)\subset V(\mathcal{H}) and there is a bijection f:E(G)E(H)f:E(G)\rightarrow E(\mathcal{H}) such that for any edge ee of GG we have ef(e)e\subset f(e). We study Ramsey problems for Berge copies of graphs, i.e. the smallest number of vertices of a complete rr-uniform hypergraph, such that if we color the hyperedges with cc colors, there is a monochromatic Berge copy of GG. We obtain a couple results regarding these problems. In particular, we determine for which rr and cc the Ramsey number can be super-linear. We also show a new way to obtain lower bounds, and improve the general lower bounds by a large margin. In the specific case G=KnG=K_n and r=2c1r=2c-1, we obtain an upper bound that is sharp besides a constant term, improving earlier results.

Keywords

Cite

@article{arxiv.1906.02465,
  title  = {On Berge-Ramsey problems},
  author = {Dániel Gerbner},
  journal= {arXiv preprint arXiv:1906.02465},
  year   = {2019}
}

Comments

8 pages

R2 v1 2026-06-23T09:44:55.531Z